In co-pending International patent application number PCT/AU92/00575 a Gas Delivery System is disclosed for delivering gaseous fuel to a spark-ignited internal combustion engine. Gaseous fuel is delivered to a region adjacent to a source of ignition, the region comprising a pre-combustion zone and a combustion zone in fluid communication with each other. Combustion of the gaseous fuel is initiated in the pre-combustion zone and the resultant effects of gaseous fuel ignition are directed to achieve combustion of the remaining gaseous fuel in the combustion zone. The relative proportions of gaseous fuel delivered to the pre-combustion zone and combustion zone respectively is carefully controlled to achieve a minimum fuel/air ratio or lean burn regime.
The non-return valve of the present invention was developed for controlling the delivery of gas to the pre-combustion zone however, as noted above, it may have application elsewhere for controlling the flow of a fluid in one direction.